4.2 a Flashcards
ore
rock that contains metals that can be extracted
what is steel
alloy of iron and carbon, as well as some other elements (which depend on required properties)
environmental implications of extracting metal from ores
need to replace natural resources
very high energy consumption
economic implications of extracting metal from ores
gov spending
effect on business climate
stable economic growth that can trickle down to local communities
social implications of extracting metal from ores
developing goods that can enhance human well being
empowering local communities
what affects metal durability
its grain size
large grains are formed through…
slow cooling
small grains are formed through…
rapid cooling
large grains have increased…
tensile strength
toughness
ductility
which grains are more likely to snap
smaller ones
alloys
modifies properties of metals. combining at least one metal w other materials to produce another that is more useful for a specific task
list common alloys
brass
bronze
steel
copper
what does alloying generally do in comparison to pure metals
increases strength and hardness while decreasing ductility
superalloys + where they’re often used
alloy that exhibits excellent mechanical strength, resistance to creep deformation, resistance to corrosion
their biggest requirement is to maintain high mechanical strength within extreme temperatures, so hugely used in aerospace, formula 1, nuclear reactors etc
creep in relation to metals
tendency of a metal to slowly deform permanently due to long term exposure to stress.
creep is more dramatic under higher temps
work hardening
toughening metal through plastic deformation. metal is not heated at all
tempering
heating process that generally comes after work hardening; increases toughness of metal
annealing
metal is heated and allowed to cool slowly to be made easier to work with – increases ductility
ferrous metals
contain iron
which metals are magnetic
ferrous
potential issues w recovery and disposal of metals
not all alloys are identifiable – might require sophisticated techniques to identify composition
some have lower melting points => can vaporise during recycling process and cause pollution
how is it better to recycle metal over plastic
metals and alloys can be indefinitely recycled, unlike plastic which degrades when recycled
